Fuzz or property test deserialization with random bytes

[teor2345]

Motivation

In Zebra, we do some random struct serialization round-trip property tests (#27).

But we don't take random bytes and try to deserialize them. This means that it's harder to catch security issues like #2263.

API Reference

proptest has Arbitrary random data implementations for fixed-size byte arrays and variable-size byte vectors:
https://docs.rs/proptest/1.0.0/proptest/arbitrary/trait.Arbitrary.html

Solution

For each deserialized type:

• deserialize a random fixed-size byte array or variable-sized byte vector
  • if deserialization panics, fail the test
• if deserialization is successful, serialize the type back into bytes, and check that they match

Try to prioritise smaller types over larger types, because a lot of larger types are just aggregates of smaller types.

Issues

• Coverage-based fuzzing for transaction processing, (de)serialization #2298
• Coverage-based fuzzing for network message processing, (de)serialization #2299
• Coverage-based fuzzing for block processing, (de)serialization #2300

Alternatives

If we don't do this, we risk panic security vulnerabilities.

Related Work

Use property testing for message struct serialization round-trips #27 - goes from random types to bytes and back

[mpguerra]

Converted to an issue

[teor2345]

This is a useful test, but it's not urgent.